git/stats: Report garbage in packfile directory

Start reporting garbage files in packfile directories. This helps us to
abandon the external git-count-objects(1) process.

2 files changed, 25 insertions, 6 deletions

diff --git a/internal/git/stats/objects_info.go b/internal/git/stats/objects_info.go
index 22f4bccb5..13b8d838c 100644
--- a/internal/git/stats/objects_info.go
+++ b/internal/git/stats/objects_info.go
@@ -173,6 +173,10 @@ type PackfilesInfo struct {
 	Count uint64 `json:"count"`
 	// Size is the total size of all loose objects in bytes, including stale ones.
 	Size uint64 `json:"size"`
+	// GarbageCount is the number of garbage files.
+	GarbageCount uint64 `json:"garbage_count"`
+	// GarbageSize is the total size of all garbage files in bytes.
+	GarbageSize uint64 `json:"garbage_size"`
 }
 
 // PackfilesInfoForRepository derives various information about packfiles for the given repository.
@@ -193,10 +197,6 @@ func PackfilesInfoForRepository(repo *localrepo.Repo) (PackfilesInfo, error) {
 
 	var info PackfilesInfo
 	for _, entry := range entries {
-		if !strings.HasSuffix(entry.Name(), ".pack") {
-			continue
-		}
-
 		entryInfo, err := entry.Info()
 		if err != nil {
 			if errors.Is(err, os.ErrNotExist) {
@@ -206,6 +206,23 @@ func PackfilesInfoForRepository(repo *localrepo.Repo) (PackfilesInfo, error) {
 			return PackfilesInfo{}, fmt.Errorf("getting packfile info: %w", err)
 		}
 
+		// We're overly lenient here and only verify for known prefixes. This would already
+		// catch things like temporary packfiles, but it wouldn't catch other bogus files.
+		// This is on purpose though because Git has grown more and more metadata-style file
+		// formats, and we don't want to copy the list here.
+		if !strings.HasPrefix(entry.Name(), "pack-") {
+			info.GarbageCount++
+			if entryInfo.Size() > 0 {
+				info.GarbageSize += uint64(entryInfo.Size())
+			}
+
+			continue
+		}
+
+		if !strings.HasSuffix(entry.Name(), ".pack") {
+			continue
+		}
+
 		info.Count++
 		if entryInfo.Size() > 0 {
 			info.Size += uint64(entryInfo.Size())
diff --git a/internal/git/stats/objects_info_test.go b/internal/git/stats/objects_info_test.go
index 4ab97d0a7..b70fd683a 100644
--- a/internal/git/stats/objects_info_test.go
+++ b/internal/git/stats/objects_info_test.go
@@ -363,8 +363,10 @@ func TestPackfileInfoForRepository(t *testing.T) {
 		}
 
 		requirePackfilesInfo(t, repo, PackfilesInfo{
-			Count: 2,
-			Size:  2,
+			Count:        2,
+			Size:         2,
+			GarbageCount: 1,
+			GarbageSize:  1,
 		})
 	})
 }